The invention disclosed and claimed herein generally relates to telephone logging equipment and more particularly to apparatus for bridging a digital telephone line and converting the digital signals to analog signals for logging purposes.
The logging of telephone calls by businesses has long been utilized for purposes of quality control, training new employees, archival recording or simply the monitoring of telephone calls. Such logging activity is typically carried on by businesses engaged in telemarketing, sales and customer service, transactions with financial institutions such as stock brokers and banks or insurance companies, and in numerous other applications where it is desired to preserve the information being communicated during telephone calls. The kind of telephone system typically utilized by such business organizations includes a PBX or other call switching and control device which is typically coupled through a plurality of telephone lines to individual telephone sets used in the various offices of the organization. The PBX is typically a digital device as are the individual telephone devices connected to the PBX. Therefore the signals that are coupled between these devices travel on digital signal lines.
In order to log calls occurring on these digital signal lines, it is necessary to provide a bridging tap to tap into each individual line while maintaining line continuity and route the signal through another digital telephone signal line to a decoder unit which may comprise a digital-to-analog converter (DAC) for each digital line capable of being monitored. Each DAC converts the monitored digital telephone signal into an analog form so that it may be conveniently logged or recorded by an analog recording device. Thus, when listening to the signals that have been logged by the above described apparatus, a person may understand the conversation directly.
The principle components of a logging apparatus includes the bridging tap device and a decoder unit (which may include the individual DAC circuits), and a wide band, shielded cable of substantial length running between the bridging tap and the decoding unit. The bridging tap is typically part of the distribution frame for the plurality of digital telephone lines. However, the wide band, shielded cable that routes the tapped digital telephone signals to a decoder unit and the decoder units are typically mounted in back plane assemblies which are usually mounted in equipment cabinets which occupy considerable space and requires substantial technical skill for installation and maintenance. Moreover, the wide band signals are susceptible to noise, distortion and interference that arise because of the broad band nature of the digital tapping cable running between the bridging taps and the decoder units as well as the termination impedance mismatches or connector integrity problems that may occur at each termination of a wide band cable.
Thus, what is needed is a simpler logging tap system which eliminates the wide band cables required to connect the bridging taps to the decoder units and minimize the opportunities for noise, distortion and interference or unreliability of connections that may occur in the prior art system. Moreover, a system needing these requirements would also be easier to install and maintain as well as providing for much simplified retrofitting of logging systems as the business organization having the telephone system expands.
There is provided according to the present disclosure a logging tap for the direct connection of decoder unit having a plurality of digital-to-analog converter DAC inputs to a plurality of digital telephone signal lines in telephone logging applications. The logging tap comprises a decoder unit supported on a planar substrate and having a plurality of DAC circuits, an input terminal for coupling each of the input digital telephone signals to a corresponding DAC circuit input and an output terminal for coupling the analog signal output of the corresponding DAC circuit to a recording device for logging; a type 66 block having first and second rows of insulation displacement pins disposed as circuit pairs in each said first and second row, each circuit pair for bridging at least one of the plurality of digital telephone lines coupling a PBX to one of a plurality of a subscriber""s digital telephone devices; and an adapter having a first plurality of extension terminals for connecting each of the ID pins of the first row of terminals of the type 66 block to a corresponding input terminal of the corresponding DAC circuit and having a second plurality of extension terminals for connecting each of the ID pins of the second row of terminals of the type 66 block to a corresponding output terminal of the corresponding DAC circuit.